Aspirator type spray apparatus having a miniature spray head



Jan. 4, 1966 ASPIRATOR TYPE SPRAY APPARATUS HAVING A MINIATURE SPRAY HEAD B. BARTEL 3,227,377

Filed Feb. 17, 1964 4 ON-OFF VALVE (u j:Y:1A R

7 1.9 L4 2a /a INVENTOR BENNO BARTEL AGENT United States Patent M i 3,227,377" ASPIRATOR TYPE SPRAY APPARATUS HAVING A r MINIATURESPRAYHEAD r Benno Bartel, Harrisville, .R.I.," assignonjo :North American Philips Company, Inc., New York, N.Y., a corporation of Delaware 7 l Filed Feb. 17, 1964, Ser. No.; 345,491 Claims. (Cl. 239-.-124)' This invention relates to an aspirator' type spray device and in particular to an improved device of this type having a miniature spray nozzle or head.-

Presently; known aspiratortype Sprayers are difiicult, if not impossible, to miniaturize because of the capillary effect in the minute passages :of themspray..nozzle-uThis eifect results in the formationof largedropletswhen the device is placed in operation, after a short period ofidleness. The formation of largedroplets withimthe nozzle by capillary action is intolerable sincerthese. droplets cause splashing when the spray is first turned onff 6.

Another major problem with miniaturizing presently known sprayers is that they cannot handle material which can crystallize .within-.the small passag'esxof the .nozzle if the. quantity of,solvent is not carefully maintained at the necessary minimum. .1 a

According. to this invention, thjese problemsuare overcome by continuously circulating fluid as hereinafter more fully described. p r

In addition -to overcoming the foregoing disadvantages, the apparatus according to the'invention provides instantaneous on and OK control of spray and a plurality of adjustments can be provided for optimum operation in any position of the nozzle and/ or fluid container.

An object of the invention .is toprovide aminiature aspirator spray device having the features and advantages noted hereinabove.

The present primary object of this invention is to provide a miniaturized aspirator spray device which is particularly useful for spraying solder flux on the lead wires of semi-conductor devices prior to soldering.

The foregoing objects and advantages of the invention will be apparent from the presently preferred embodiment illustrated in the attached drawing wherein the sole figure is a simplified elevational, partly sectional, side View of the apparatus.

The spray apparatus illustrated comprises a variable nozzle member, generally designated 10, and a control valve, container combination generally designated 20.

The nozzle is mounted on a machine (not shown) and comprises an adjustable head piece 1 within a bore of the nozzle housing. As shown in the drawing, the head piece 1 and its bore are threaded to provide for axial adjustment but any other suitable arrangement may be used. Head piece 1 has an outlet aperture 2 and an enlarged inner bore 5 coaxial with the outlet aperture 2. The shoulder 6 formed between aperture 2 and bore 5 defines an adjustable nozzle valve with the shoulder 7 of the fixed nozzle aspirator stem 3 having a reduced tip portion 8. The space between shoulders 6 and 7 therefore defines a variable venturi orifice or valve for controlling the volume of air passing over the tip 8 of stem 3 from which the liquid to be sprayed is withdrawn by aspiration effects. The air supply for the nozzle is provided by a pipe 4 connected in any suitable manner with nozzle 10 and communicating with an appropriate internal passage 9 within the nozzle 10.

A flexible hose or conduit 11 interconnects the nozzle stem 3 with a liquid container 14 having a standpipe 15. A second flexible conduit 12 interconnects the air pipe 4 with a second aspirator stem 16 secured Within a bore 17 of the container cover 13. Between the stem 16 and the the stem 3 which is returned to the container.

3,227,377 Patented Jan. 4, 1966 ice reduced diameter portion of bore 17 of the cover a relativelyfixed constricted throat or venturi 18 is formed. A second air pipe communicates with the bore 17 in the container cover above the venturi 18 and is connected with a positive pressure air source (not shown) via a flexible hose 19; The cover 13 has a vent 21 within which a bent lever 22 may be pivotally mounted at 23. One end of lever 22 comprises a handle while the other-end of the lever is provided with a suitable closure for the opening and closing venturi throat 18.

As shown by dashed lines in the figure, when the handle of lever 22 is depressed, the venturi opening 18 is closed so that air from a positive pressure source is conducted through'stem 16 to nozzle 10 via adjustable valve25,*hose 1'2, nozzle stem 3' and outlet 2. In the position of lever 22 shown in solid lines, the air under pressure escapes from venturi throat 18 into the container and is vented to atmosphere through opening 21 in the cover 13 and thereby creates a reversed air fiowin the nozzle i.e. air is drawn through the nozzle aperture 2 through the restriction define'd by shoulders 6 and 7,'through pipe 4, hose 12, valve 25 and into container 14 via the stem 16. "Thus a small negative pressure is created at the-end of nozzle stem 3 within the aperture 2 which will create a small recirculating flow to exist in the minute bore of The slow but continual circulation of liquid inthe bore of stem 3 .(whichrnay have a diameter on the order of 0.'007 inch) prevents accumulation of liquid by capillary action and also prevents solidification or crystal formation within this small bor'e. In the case of liquid soldering flux, the loss of solvent in the nozzle passages readily causessolidification andblinding or plugging. However, continual circulation back to the container overcomes nozzle plugging from this cause. Also, of course, when the device is turned on the liquid is immediately available for spraying since the liquid carrying line remains full even though the spray device is not in operation.

It will be apparent from the foregoing description of the invention that the problems of capillary droplet formation resulting in splashing, and the prevention of plugging due to crystallization are overcome by continuous circulation of the spray material when spraying is interrupted. It will be apparent from the foregoing the off condition of the apparatus is positive in action and also that continuous recirculation provides instantaneous response to the on condition of the apparatus. Likewise the response time of the device is independent of the liquid level of spray material in the container. That is, in the presently known devices, the spray liquid in the conduits leading to the nozzle can drain back into the container when the device is turned oil for a short time, whereas in the invention above described the liquid cannot drain back to the container nor can the liquid head in the container have any effect on the response time of the apparatus when it is turned on. The partial vacuum at the tip of the stem 3 and the high pressure in the container 14 assure a high liquid level in the standpipe 15 and hose 11 independent of the liquid level in the container. Regarding the 011 condition of the apparatus it will be apparent that uncovering the aperture 18 immediately and positively cuts off the spray since the aspiration of venturi 18 immediately draws the spray material back to the container. It will be apparent to those skilled in the art that the apparatus according to the invention may be adjusted for optimum operation by virtue of the adjustable valve in the nozzle 10 and the valve 25 in the air line 12.

I claim:

1. Miniature aspirator type spray apparatus comprising a nozzle, an air passage in said nozzle terminating in a discharge outlet, means defining a constriction in said air passage, a source of liquid, a nozzle stem piece having one end connected with said source of liquid for withdrawing liquid therefrom and the other end operatively connected with the constriction of said air passage for discharging said liquid through said outlet, a conduit normally supplying air under pressure to said air passage, said conduit having a second stem piece and an associated constricted throat opening into said source of liquid, and means for venting said conduit to atmosphere through said second constricted throat and said source of liquid for creating a negative pressure in said air passage and returning liquid in said nozzle to said liquid source.

2. An aspirator type spray device comprising a miniature spray nozzle having a stern, means connecting said stem with a source of liquid at one end thereof and a reduced portion at the other end of said stem, means defining an air passage in said nozzle adjacent said reduced portion of said stem, conduit means including an aspirator means connecting said air passage and said source of liquid, and means for alternatively creating both a positive pressure in said air passage and a negative pressure in said air passage for returning liquid to said liquid source.

3. Miniature aspirator type spray apparatus comprising a nozzle, an air passage in said nozzle terminating in a discharge outlet, means defining a constriction in said air passage, a nozzle stem piece having one end connected with a source of liquid and the other end operatively connected with the constriction of said air passage for withdrawing liquid from said stem and discharging said liquid through said outlet, a conduit normally supplying air under pressure to said air passage, said conduit having a second stem piece and an associated constricted throat, and means for venting said conduit to atmosphere through said second constricted throat for creating a negative pressure in said air passage, said means for venting said conduit to atmosphere comprising a container for said source of liquid having a vent in the cover thereof.

4. An aspirator type spray device comprising a miniature spray nozzle having a stem, means connecting said stem with a source of liquid at one end thereof and a reduced portion at the other end of said stem, means defining an air passage in said nozzle adjacent said reduced portion of said stem, an adjustable head piece surrounding said reduced portion and defining a variable constriction in said air passage adjacent the reduced portion of said stem, conduit means including an aspirator means connecting said air passage and said source of liquid, and means for alternatively creating both a positive pressure in said air passage and a negative pressure in said air passage for returning liquid to said liquid source.

5. Miniature aspirator spray apparatus comprising a nozzle, an air passage in said nozzle terminating in an axially adjustable head piece having a discharge outlet, a stem in said nozzle having a reduced portion at one end, said stern being connected at its other end with a source of liquid, said head piece having a first bore concentric with said stem and having a diameter proportional to the outside diameter of said stem, a second bore in said head piece concentric with said reduced portion and having a diameter proportional to the outside diameter of said reduced portion; a container having said source of liquid therein, a cover for said container, a vent in said cover, a second stem having a reduced portion at one end in said cover, a conduit interconnecting the other end of said second stem with said air passage, an aperture in said cover having a first portion proportional to and concentric with said second stem and a second portion proportional to and concentric with the reduced portion of said second stem, said second portion of said aperture having an opening to said container, means connecting said aperture with a source of air under pressure, and means for opening and closing said opening to said container.

References Cited by the Examiner UNITED STATES PATENTS 1,986,476 1/1935 Ironside 141-28 2,283,762 5/1942 Robinson 2391l9 X 2,640,724 6/1953 Sanders et al 239-1 19 X RAPHAEL M. LUPO, Primary Examiner.

HADD S. LANE, Examiner. 

1. MINIATURE ASPIRATOR TYPE SPRAY APPARATUS COMPRISING A NOZZLE, AN AIR PASSAGE IN SAID NOZZLE TERMINATING IN A DISCHARGE OUTLET, MEANS DEFINING A CONSTRICTION IN SAID AIR PASSAGE, A SOURCE OF LIQUID, A NOZZLE STEM PIECE HAVING ONE END CONNECTED WITH SAID SOURCE OF LIQUID FOR WITHDRAWING LIQUID THEREFROM AND THE OTHER END OPERATIVELY CONNECTED WITH THE CONSTRICTION OF SAID AIR PASSAGE FOR DISCHARGING SAID LIQUID THROUGH SAID OUTLET, A CONDUIT NOR- 